The present invention pertains to connector apparatus. More specifically, it pertains to apparatus suitable for connecting pipes in particularly difficult environments such as subaquatic ones.
2. Description of the Prior Art
It is known to connect pipes together using tapered slip wedges, which have conical outer surfaces and circumferentially grooved cylindrical inner surfaces, by urging the wedges along an inwardly tapering abutment wall to cause the slips to move radially inwardly relative to a connector sleeve for clamping the external surface of a pipe. In existing forms of such connectors, the slips are generally forced apart by the application of fluid under pressure to an annular piston or a plurality of piston rams arranged around the axis of the pipe connector.
Such an arrangement has been proposed for use in subaquatic environments, for example in the connection of pipelines for conveying liquid hydrocarbons from a submarine well. Examples of such apparatus may be seen in U.S. Pat. No. 3,393,926 and British Pat. Nos. 1,285,803 and 1,368,122. One advantage of such apparatus is the fact that the driver need only connect a source of hydraulic pressure to a pressure port on the connector to enable opposed slips to be driven into an engaged position to lock the connector against the pipe.
However, such arrangements have a disadvantage in that when the hydraulic pressure source is later disconnected from the pipe connector there are problems of sealing against escape of hydraulic fluid in order to prevent relaxation of the slips. One way of overcoming this disadvantage is to use a setting resin as the hydraulic medium so that the resin is allowed to set to hold the slips in position and once the resin has set it cannot escape. However, once the resin has hardened it is not possible to later apply additional slip engaging displacement to the connector for further tightening or release of the connector.